This proposal details a three year training grant focused on development of an independent investigator in the field of molecular food safety microbiology. The principal investigator has completed a structured residency in Veterinary Large Animal Internal Medicine and is board certified by the American College of Veterinary Internal Medicine in this specialty. He is now actively pursuing intensive training in the field of molecular microbiology to complement his expertise in large animal infectious disease. This program is designed to provide exposure to a broad range of classical and contemporary molecular techniques applicable to hypothesis driven research in food safety microbiology. Through the mentorship of Dr. Qijing Zhang, a leader in the field of Campylobacter molecular microbiology, the principal investigator will develop his ability to formulate thoughtful hypotheses, design robust experiments to test these hypotheses and communicate scientific results with peers. Special emphasis will be placed on training in responsible conduct of research. At the completion of the program it is expected that he will be prepared for an independent career in academic research. Research conducted as part of this proposal will focus on the quorum sensing mechanism employed by Campylobacter jejuni, a leading cause of human foodborne bacterial enteritis in the United States. Autoinducer-2 (AI-2) mediated bacterial communication has been described in over 30 bacterial species and is responsible for coordinating expression of a variety of adaptive responses. Building on the results of preliminary research designed and conducted by the principal investigator, this study will 1) determine the effect of the G92D amino acid substitution on the enzymatic activity of the C. jejuni LuxS protein, 2) characterize a two-component sensor system (homologous to a phosphorus responsive two-component sensor system of E. coli) regulated by the presence of AI-2, and 3) examine the effects of the luxS null mutation on the adaptation of Campylobacter to various environments using in vitro and in vivo experiments. Results of these studies will provide the first comprehensive description of this signaling system in Campylobacter and will provide a strong foundation for future independent research endeavors by the investigator. The Department of Veterinary Microbiology and Preventative Medicine at Iowa State University is a leader in food safety and public health microbiology. The combined resources of the University and the local USDA National Animal Disease Center provide an environment rich in expertise and learning unmatched in the veterinary field. Given the expertise of the mentor's laboratory in the field of study, the fertile scientific environment, and a strong institutional commitment, this training program is assured success.